Black smoke coming from Carnival Dream stack

[SuiteTraveler]

Not sure what this was. We were in Cozumel at 3 Amigos and noticed black smoke pouring from the whale tail starboard side only. The smoke went on for about 30 minutes before it finally subsided. Have not seen anything like this in around 30 cruises. We are back onboard now and everything seems ok. Anyone know what happened?

[Bonnie J.]

No, but we usually see black smoke rather than grey coming from the smoke stack. The engines are never turned off so that's where it has to come from.

[CruiserBruce]

You are on the ship, correct? I would be asking crew, perhaps other pax. Not here.

[navybankerteacher]

Dream's propulsion system is diesel electric- where Diesel engines power the generators. Ordinarily when in port only some of the Diesel engines are running- and from time to time one may be taken off line and another started up. Black smoke from a diesel exhaust indicates improper fuel/air mixture which results in unturned fuel particulates going up the stack; and this often happens when an engine is started and existing particulate in the exhaust system is added - resulting in heavy clouds of black smoke until the fuel/air mixture is adjusted and the existing particulate is blown out.

 

Ugly, but not overly unusual.

[sail7seas]

You are on the ship, correct? I would be asking crew, perhaps other pax. Not here.

 

:) Good point. tHhey are more likely to know.

[Nitemare]

Black smoke from a whaletail is never a good thing!

[chengkp75]

Dream's propulsion system is diesel electric- where Diesel engines power the generators. Ordinarily when in port only some of the Diesel engines are running- and from time to time one may be taken off line and another started up. Black smoke from a diesel exhaust indicates improper fuel/air mixture which results in unturned fuel particulates going up the stack; and this often happens when an engine is started and existing particulate in the exhaust system is added - resulting in heavy clouds of black smoke until the fuel/air mixture is adjusted and the existing particulate is blown out.

 

Ugly, but not overly unusual.

 

Yes, at start up, the diesel engine's turbocharger is not spinning fast enough to compress enough air to match the fuel required to start the engine. Just look at buses and trucks starting from a traffic light. Once there is sufficient energy in the exhaust gas to get the turbocharger spinning, the air/fuel mixture is optimal and the smoke goes away. This normally will only happen for 10-15 seconds during start up.

 

My guess is that either a fuel pump on one of the diesels stuck during start up, putting too much fuel into the engine for the required load, causing incomplete combustion, and it took a few minutes for the engineers to notice this, or that one of the boilers was acting up, and these are more prone to extended smoking intervals if combustion is not optimum. Less common, particularly in port, is "blowing tubes" of the boilers, where steam is used to clean soot from the outside of boiler tubes to improve heat transfer. This is most often done at night, at sea.

 

Different engines and different boilers will exhaust out the different sides of the "whale tail" stack.

Edited June 17, 2016 by chengkp75

[leaveitallbehind]

Yes, at start up, the diesel engine's turbocharger is not spinning fast enough to compress enough air to match the fuel required to start the engine. Just look at buses and trucks starting from a traffic light. Once there is sufficient energy in the exhaust gas to get the turbocharger spinning, the air/fuel mixture is optimal and the smoke goes away. This normally will only happen for 10-15 seconds during start up.

 

My guess is that either a fuel pump on one of the diesels stuck during start up, putting too much fuel into the engine for the required load, causing incomplete combustion, and it took a few minutes for the engineers to notice this, or that one of the boilers was acting up, and these are more prone to extended smoking intervals if combustion is not optimum. Less common, particularly in port, is "blowing tubes" of the boilers, where steam is used to clean soot from the outside of boiler tubes to improve heat transfer. This is most often done at night, at sea.

 

Different engines and different boilers will exhaust out the different sides of the "whale tail" stack.

 

Your responses are always very much appreciated and always provide a clear understanding of whatever issue is at hand. Thank you for taking the time to educate all of us!

[flamomo]

OR perhaps the burnable trash was being disposed of in the incinerator.

[navybankerteacher]

 

...

 

Less common, particularly in port, is "blowing tubes" of the boilers, where steam is used to clean soot from the outside of boiler tubes to improve heat transfer. This is most often done at night, at sea.

 

...

 

/QUOTE]

 

But certainly not when upwind of the squadron commodore when steaming in formation.

[chengkp75]

OR perhaps the burnable trash was being disposed of in the incinerator.

 

Incinerators are not allowed to operate in port, and when they do operate, there are diesel burners in them to keep the smoking within prescribed limits or the unit will shut down, certainly before 30 minutes.

[Nanobot]

Another possibility, since she was in port, is that they may have turned-on the emergency generator for a regular check.

[chengkp75]

Another possibility, since she was in port, is that they may have turned-on the emergency generator for a regular check.

 

Typically, the emergency generator does not exhaust out the stack like the other engines, though some might. But, again, the smoke would only last 5-10 seconds while starting.